1. Field of Invention
Aldehydes and ketones have been reported to be chemically converted to hydroxyaldehydes, polyhydroxyaldehydes, hydroxyketones and/or polyhydroxyketones in the presence of acids, neutral ionic species and/or bases. A number of reactions have been disclosed for formation of products at elevated temperatures, long reaction times and predominantly low conversion efficiencies but formation of products of controlled molecular weight or carbon-carbon chain length has not been taught. The invention taught in this application is chemical conversion of aldehydes, containing two or more carbon atoms, to products of selected carbon chain length using inorganic bases in a specific concentration range at sub-ambient temperatures. In addition ketones have been catalytically converted to solid products.
The subject of this application is a key step in the catalytic chemical conversion sequence of cellulose to ethanol, ethanol to acetaldehyde then to polyhydroxy aldehydes of specific molecular weight for final conversion to aliphatic hydrocarbons, namely gasoline by methanation or hydrogenation. By forming hydroxyaldehyde or hydroxyketone products of selected molecular weight in substantial yields gasoline can be produced from natural renewable products grown in this country without the expensive refining process and without the need for petroleum.
2. Description of Prior Art
The chemical and fuel processing industries have grown to maturity using petroleum feed stocks. Petroleum is a non-renewable, depleting resource that may become unavailable in the next 100 years. This planet Earth fosters continual growth of numerous carbohydrate based plants including trees, grasses, grains, fruits and vegetables plus their supporting cellulosic plant stalks and related natural waste materials for recycle. Grains, corn cobs, prairie grasses and other cellulosic materials are subject to bio-fermentation, thermal and catalytic processes producing ethanol and related products. A major industry is rapidly developing in ethanol production and much of the product is sold as combustion engine fuel or its additive. Ethanol is becoming more available as a renewable resource and this application teaches conversion of aldehydes, including acetaldehyde derived from ethanol to valuable intermediates for use in production of gasoline and industrial chemical intermediates.
The invention disclosed in this application teaches chemical conversion of aldehydes containing two or more carbon atoms and ketones to products of selected molecular weight of hydroxyaldehydes, polyhydroxyaldehydes, hydroxyketones and/or polyhydroxyketones in liquid phase using a specific concentration range of soluble inorganic base. This process provides a method for production of concatenated carbon-carbon backbone reactive molecules of predetermined chain length. For example, C2 reactant aldehydes, such as acetaldehyde, are converted to C4 through C8 for a dilute base, C8 through C12 for a slightly more concentrated base and C12 through C30 for more concentrated base. Such concatenated carbon-carbon backbone molecules become a basis for manufacture of hydrocarbon fuels and industrial chemical intermediates by means of a reduction process. For example, the concentration range of C8 through C12 affords direct conversion to gasoline fuel.
There are a number of hot tube gas reactions reported for preparation of low concentrations of hydroxyaldehydes, hydroxyketones and/or unsaturated aldehydes conducted by passing aldehyde or ketone vapors over supported catalysts at elevated temperature. There are also some slower liquid phase reactions producing much less than a majority of products. U.S. Pat. No. 6,586,636, issued Jul. 1, 2003, introduced a process for preparation of unsaturated aldehydes from straight chain C3, C4 or C6 vaporized aldehydes on a catalyst at 175° C. to 350° C. U.S. Pat. No. 6,552,232, issued Apr. 22, 2003, disclosed preparation of aldol products from aldehydes in ionic medium on supported base catalyst at −20° C. to 300° C., preferably 80° C. to 90° C. in a period of three hours at pressures of 1 atmosphere to 1000 atmospheres. This application makes use of neutral ionic liquid media and a basic catalyst where the ionic liquid medium is selected from 1-butyl-3-methyl imidazolium, 1-butyl-2,3-dimethyl imidazolium, 1-butyl-pyridinium, pyridinium or imidazolium species, and derivatives thereof, BF4 ion and PF6 ion species as well as basic catalyst comprising hydroxide species. U.S. Pat. No. 6,090,986, issued Jul. 18, 2000, discussed formation of esters from C9 alcohols formed from a C6 aldehyde and propanal by an aldol process producing >35% product then hydrogenating the unsaturated aldehyde to a saturated C9 aldehyde. U.S. Pat. No. 4,017,537, issued Apr. 12, 1977, taught preparation of aldol products from aldehydes with the aid of an esterfying agent at 150° C. to 280° C. U.S. Pat. No. 4,247,653, issued Jan. 27, 1981, discussed formation of up to 40% hydroxyaldehyde products from formaldehyde in a temperature range of 10° C. to 150° C. There are also a number of records of prior art disclosing application of supported transition metal catalysts for both formation of aldehydes and for their reaction to products at elevated temperatures and pressures by means of an aldol condensation process. These reactions appear to be slow and do not teach formation of products of a controlled carbon-carbon chain length useful for gasoline production of other specific range hydrocarbon formation.
The invention taught in this application is chemical conversion of aldehydes, containing two carbon atoms or more, to products comprising hydroxyaldehydes and/or polyhydroxyaldehydes of controlled carbon chain length using selected concentrations of soluble inorganic bases at sub-ambient temperatures. This application also teaches catalytic conversion of ketones to products comprising hydroxyketones and/or polyhydroxyketones.
It is an object of this invention, therefore, to provide chemical conversion of aldehydes, containing two carbon atoms or more, to products comprising hydroxyaldehydes and/or polyhydroxyaldehydes of controlled carbon chain length using selected concentrations of soluble inorganic bases at sub-ambient temperatures. It is another object of this invention to teach sub-ambient conversion of acetaldehyde reactants to products comprising 3-hydroxybutyraldehyde (C4) using 0.0005 g/mL of soluble base, 3-hydroxybutyraldehyde and 3,5-dihydroxyhexeraldehyde (C4 and C6) using 0.004 g/mL of soluble inorganic base, C6 to C14 using 0.03 g/mL of soluble base, C12 to C32 using 0.05 g/mL of soluble base and greater than C100 using 0.3 g/mL of the soluble portion of inorganic bases comprising sodium, lithium, potassium, rubidium, cesium, magnesium, calcium, barium, strontium hydroxides, carbonates, bicarbonates and/or phosphates. It is still another object of this invention to teach catalytic conversion of ketones to hydroxyl ketones and polyhydroxy ketones. Other objects of this invention will be apparent from the detailed description thereof that follows, and from the claims.